1. Field of the Invention
The present invention relates to a method for the preparation of rubber, and more particularly to a method for the preparation of foamed and crosslinked rubber.
2. Description of the Prior Art
Rubber is a material with high resilient, good recoverability, good fatigue resistance, ski-proofing property, and abrasion proofing property, thus is has been commonly used in daily life and has become one of the most important material in the industry.
Conventional methods of preparation of foamed and crosslinked rubber include one-stage crosslinking and foaming manner, two-stage crosslinking and foaming manner, and continuous crosslinking and foaming manner.
The one-stage manner mainly includes single heating step to crosslink and foam the rubber raw material. Products made by such one-stage manner are usually limited to small size articles, low foaming degree, and low crosslinking degree.
The two-stage manner mainly includes two heating steps to crosslink and foam the rubber raw material. Specifically, the raw material is mainly shaped in the first heating step, and then is matured and enlarged in the second heating step. Products made by the two-stage manner are usually simple-structured. For example, they may be formed into a plate shape.
The continuous manner mainly includes heating the raw material continuously to crosslink and foam the rubber.
Some disadvantages are arisen in the conventional rubber preparation manners. For instance, the crosslinking degree of the rubber cannot be easily controlled, the product may be damaged while parting the product from the mold, and the patterns in the mold are not well copied on the rubber products. Other disadvantages, such as product deformation, low dimensional stability, low clearness of product contour, are also commonly seen in the conventional manners.
At the present, subsequent processing and shaping steps are provided to make up the above-mentioned unsatisfied shaping result.
However, such subsequent steps will lead to new disadvantages such as high cost, low efficiency. Besides, only a few modifications can be made to the matured rubber products since the crosslinking degree of the products is too high to be further thermally shaped. In other words, seriously modifications are not likely to be achieved on the matured rubber products during the subsequent steps.
The present invention is, therefore, arisen to obviate or at least mitigate the above mentioned disadvantages.